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In between bike sizes: Cannondale Althea 2


I am considering purchasing the Cannondale Athena 2 bike. I am 5’ 6” female and fall right in the middle of the sizing guidelines. I am not sure if I should order a small or medium frame. Can I get some thoughts? I have an old Diamondback Sorrento that has been comfortable, but I don’t know what size it is and how it would compare to the Athena 2 on size and geometry. I’m definitely a novice and kind of overwhelmed by all of the details in the specs.

I will be riding neighborhood roads and easy mountain trails/paths.  My arms and legs are pretty even, I measured my ape index and am equal in wingspan/height. 

I do have severe scoliosis and am prone to back pain, so hoping to find a good comfortable fit.
I chose the Athena 2 because of its lighter weight and front suspension/disc brakes. I like the idea of something sized for women and want some versatility so I can ride with my kids. I’m also open to other suggestions if there is a better option for me.

Thanks for your input!

4 Replies

It comes down to preference mostly. One of the major changes will be that a larger frame has a longer "reach", the distance from saddle to handlebars. Given your back pain, I'd probably opt for smaller so that the reach is shorter, which should give you a slightly more upright riding position.

Other effects are "stack" (the vertical distance from cranks to handlebar height) which can be mitigated somewhat by just adjusting the seatpost height, and the wheelbase. A longer wheelbase on a larger frame tends to be more stable and smooth rolling, while a shorter base is more nimble and snappy. But I'd definitely rank these effects lower than the reach for your case.

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Hi there @Freshair!

Thanks for reaching out to the Community!  I want to start by saying that I think you are choosing a great bike. Based off of what you describe, I think you will be very happy with the Althea 2!

In regards to the sizing of the bike, I am 5’5” (longer legs than torso) and I have always chosen to ride a size M in a Cannondale bike. Overall I think you will find the larger size more comfortable.

One of the main considerations with fit is the stand over height. You want to be sure that getting on and especially off your bike, can be done safely. With that being said, based off of the type of riding you plan on doing, it sounds like it would be mostly  controlled stops and dismounts, so you should have no problem. 

If you wanted to compare your existing bike, you could take some measurements using the bike fitting tips in this article. I think this will help you make the wisest decision!

Hope this helps and you’re riding soon!

At REI, we believe time outside is fundamental to a life well lived.

My bike arrived last week and I thought I’d post which one I chose in case of anyone else in my situation. I chose the size small frame. I have put about 50 miles on it so far and am very happy. I think the medium would have been too much of a stretch and the stand over height may have been a little high.  I have not experienced any back pain when riding and the bike feels like a great fit! 


Thanks for the follow up! I’m so glad you were able to get the right fit and are enjoying yourself out there!

Be well!

At REI, we believe time outside is fundamental to a life well lived.